This study addresses the efficacy of interferon alpha-2b (continuation of treatment >6 months) for patients who responded to a previous treatment then relapsed with chronic hepatitis C virus (HCV) infection. The biochemical and virological response to treatment are measured at two time points: at the end of treatment and six months post treatment sustained response. Based on these markers, this continuing randomized clinical trial has preliminarily demonstrated that treatment with interferon alpha-2b benefits some previously treated HCV patients. Current studies focus on treatment approaches using drugs in combination with interferon to possibly enhance a sustained response.